Exemplary embodiments of the present invention relate to a cooperative control apparatus of a motor driven power steering apparatus for a smart parking assistant system (SPAS), and more particularly, to a cooperative control apparatus of a motor driven power steering apparatus for a SPAS, which prevents damage of the motor driven power steering apparatus by relieving response of the motor driven power steering apparatus and enables a driver to steer a vehicle while reducing vibration, even though an excessive required steering angle is inputted from the SPAS.
In general, a steering system applied to a vehicle refers to a system which enables a driver to lightly and quickly steer the vehicle by reducing a control force using an electronic control unit (ECU) according to the speed of the vehicle. The steering system is divided into an electronic control power steering system and a motor driven power steering (MDPS) system. The electronic control power steering system is constructed by adding an electronic control valve for controlling oil pressure to a hydraulic power steering apparatus using oil pressure of an existing hydraulic oil pump, and controls an assist amount. The MDPS system is driven by a motor and controls an assist amount.
Furthermore, there is a SPAS for solving a problem which may occur when a driver has difficulties in parking his/her vehicle in a parking space.
Here, the SPAS searches for a parking space using a camera, and checks whether there is an empty parking space or not. Then, when there is an empty parking space, the SPAS detects the corners of a parking line, acquires the coordinates of the corners using a distance sensor, compares the size of the parking space with that of a vehicle, and then determines whether the vehicle can be parked in the parking space or not. When determining that the vehicle can be parked in the parking space, the SPAS determines the shape of the parking line, and sets the parking direction of the vehicle according to the shape of the parking line. Then, the SPAS calculates a parking track based on the direction of the vehicle and the current position of the vehicle, and automatically parks the vehicle according to the parking track.
The above-described technology indicates a related art of the technical field to which the present invention pertains, and does not indicate a prior art.
In order for the SPAS to perform automatic parking using a motor driven power steering apparatus, a cooperative control apparatus converts a required steering angle of the SPAS into a steering angle and a steering angular speed of the motor driven power steering apparatus, and controls the vehicle while checking the control state. Accordingly, as the control state is checked while steering for automatic parking is performed, it is possible to prevent a malfunction.
However, when an excessive required steering angle is transmitted to the motor driven power steering apparatus from the SPAS, the motor driven power steering apparatus excessively responds. When such a state continuously occurs, serious damage may be applied to the motor driven power steering apparatus.
Furthermore, when the motor driven power steering apparatus is rapidly varied by an external input from the SPAS, a driver may feel a sense of difference due to the vibration of the steering angular speed.